Chapter 7 McGraw Hill Biology

autotrophs

An organism that obtains organic food molecules without eating other organisms or substances derived from other organisms; use energy from the sun or from the oxidation of inorganic substances to make organic molecules from inorganic ones.

heterotrophs

Organisms that can not obain energy from manufacturing their own food, so they obtain their energy from others

cellular respiration

the process by which energy is harvested; the oxidation of organic compounds to extract energy from chemical bonds

dehydrogenation

Chemical reaction involving the loss of a hydrogen atom. This is an oxidation that combines loss of an electron with loss of a proton.

NAD+

Nicotinamide adenine dinucleotide, a cofactor present in all cells that helps enzymes transfer electrons during the redox reactions of metabolism.

NADH

The reduced form of NAD+ (nicotinamide adenine dinucleotide). This is the most common electron carrier in cellular respiration.

aerobic respiration

when the final electron acceptor is oxygen during cellular respiration

anaerobic respiration

when the final electron acceptor during cellular respiration is an inorganic molecule other than oxygen

fermentation

when the final electron acceptor during cellular respiration is an organic molecule

electron transport chain

A sequence of electron carrier molecules (membrane proteins) that shuttle electrons during the redox reactions that release energy used to make ATP.

substrate level phosphorylation

ATP is formed by transferring a phosphate group directly to ADP from a phosphate-containing intermediate, or substrate. (energy transferred from one high energy phosphate bond to another-leaving the energy in the bond conserved

2

the synthesis of ATP can be accomplished by __ fundamentally different mechanisms

oxidative phosphorylation

Part of the electron transport chain. A process occurring in the mitochondria that results in the formation of ATP from the flow of electrons across the inner membrane to bind with oxygen and H+ ions. Accounts for most of the ATP generated by respiration.

glycolysis

occurs in the cytoplasm

converts glucose into two 3-carbon molecules of pyruvate

results in two ATP and two NADH molecules

Glucose + 2 NAD+ + 2 Pi + 2 ADP → 2 pyruvate + 2 NADH + 2 ATP + 2 H+ + 2 H2O + heat

G3P (glyceraldehyde 3-phosphate)

the result of the first half of glycolysis that consists of 5 steps of in order reactions that convert one molecule of glucose into two molecules of this 3-carbon compound

priming reactions

the first 3 reactions in glycolysis that "prime" glucose for by changing into a compound that can easily be changed into two 3-carbon phosphorylated molecules-requires the use of 2 ATP molecules

cleavage

the split of the 6-carbon diphosphate sugar into two 3-carbon monophosphate sugars.

1. Glycolysis
2. Pyruvate oxidation
3. Krebs cycle
4. Electron transport chain & chemiosmosis

the 4 stages of the complete oxidation of glucose

-10-step biochemical pathway
-Occurs in the cytoplasm
-Converts 1 glucose (6 carbons) to 2 pyruvate (3 carbons)
-Net production of 2 ATP molecules by substrate-level phosphorylation
-2 NADH produced by the reduction of NAD+

glycolysis

oxidation and ATP formation

Each G3P is oxidized, to NAD+ forming NADH. An additional inorganic phosphate is incorporated into each 3-carbon sugar phosphate. an Oxidation reaction converts the two sugar phosphates into intermediates that can transfer a phosphate to ADP to for ATP. The oxidation reactions also yield NADH giving a net energy yield of 2 ATP and 2 NADH.

pyruvate net reaction

pyruvates +NAD+ +CoA---> acetyl-CoA + NADH + CO2 + H+

2-Carbon Acetyl Group

Pyruvate is converted to a __-______ ________ ________ for the Krebs Cycle

NADH

The Krebs cycle itself does not produce a large amount of ATP, but it does produce a large amount of ______, which can transfer electrons to the electron transport chain

NADH FADH2

The nine reacitons of the Krebs Cyccle take in 2-carbon units in the form of acetyl-CoA and oxidize them transferring electrons and protons to 3 ______ and 1 _______

Condensation

Reaction 1 in the Krebs Cycle. Citrate is formed by joining acetyl-CoA to oxoloacetate. The reaction is stimulated when a cell's ATP concentration is low.

High

____ ATP concentration results in Condensation not taking place-therefore no Krebs Cycle, and acetyl-CoA is channeled into fat synthesis

Isomerization

Reactions 2 and 3. The repositioning of the hydroxly (OH-) group of citrate. Forms Isocitrate

1st Oxidation

Reaction 4. Isocrite undergoes and oxidative decarboxylation reaction. NADH and CO2 produced. Forms alpha ketoglutarate

2nd Oxidation

Reaction 5. Alpha Ketoglutarate is decarboxylated producing NADH and CO2. Forms Succinyl-CoA

Substrate-Level Phosphorylation

Reaction 6. In a coupled reaction the 4-carbon succinyl group and CoA high energy bond is cleaved driving the phosphorylation of GDP, in turn forming GTP-which then converts ADP to ATP. Forms succinate

3rd oxidation

Reaction 7. The free energy change in this reaction is not enough to reduce NAD+, so FAD becomes the electron acceptor making FADH2. Forms Fumurate

Regeneration of Oxaloacetate

Reaction 8 and 9. A water molecule is added forming Malate, which is then oxidized to produce an NADH molecule. Forms oxaloacetate and the Krebs cycle is ready to repeat again.

CO2

In the process of aerobic respiration, glucose is entirely consumed. all the C is eventually lost throughout glycolysis and the Krebs Cycle as _____

NADH de-hydrogenase

the first of the proteins to receive electrons from the electron transport chain is a complex membrane embedded enzyme called this.

mitochondria

cellular respiration takes place within this organelle in virtually all eukaryotic cells

Chemiosmosis

uses a proton gradient to make ATP

ATP synthase

molecular mechanism that uses energy from H+ ions to bind ADP and a phosphate group together to produce ATP

Phosphofructokinase

In feedback inhibition in glycolysis ______________________
is allosterically inhibited by ATP and/or citrate

Pyruvate dehydrogenase, Citrate synthetase

In pyruvate oxidation _________ ____________ is inhibited by high levels of NADH. _________ ____________ is inhibited by high levels of ATP.

ethanol fermenation

occurs in yeast, CO2, ethanol, and NAD+ are produced

lactic acid fermentation

occurs in animal cells. Electrons are transferred from NAHD to pyruvate.

deamination

the nitrogen containing side group (the amino group) is removed from each amino acid in this process

acetyl groups

the process of beta oxidation of fatty acids produces these